This invention relates generally to torsion axles and more particularly to linear or longitudinal torsion axles where the torsion axle extends in a longitudinal direction parallel to the direction of normal travel of a vehicle or trailer.
Typical torsion axles for trailers use a laterally extending axle tube that extends from one side of the trailer to the other. A single torsion shaft or two shorter torsion shafts are mounted in the axle tube with a resilient member or members surrounding the torsion shaft. See for example, U.S. Pat. No. 5,277,450 or U.S. Pat. No. 4,291,895.
Some disadvantages with typical torsion axles include: assembled axles, because of weight and size, must be shipped on flat bed trailers; typical torsion axle weight is more than 100 pounds. In addition, if the torsion axle breaks, it is normally necessary to replace the entire axle. Because the axle tube fits below the trailer floor and frame, ground clearance beneath the trailer is reduced. Sometimes, for boat trailers, the axle is bent to clear the bottom of the boat keel, reducing the ground clearance even further. As a result, to maintain necessary ground clearance, the center of gravity of a loaded trailer is increased.
The foregoing illustrates limitations known to exist in present torsion axles. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.